Calculators have enjoyed tremendous popularity in recent years. To some extent, this popularity has resulted from increased convenience associated with reductions in the overall size of calculators. In addition to increased portability due to size reduction, calculators which take up less space have proved advantageous in numerous applications where prior, larger calculators were impractical.
For example, U.S. Pat. No. 4,075,702, issued to Davies on Feb. 22, 1978, discloses a wallet enclosure for holding an electronic calculator. According to this disclosure, a thin calculator may be placed within the wallet enclosure which also serves as a checkbook, thereby providing easy access to electronic calculation when writing checks. The wallet enclosure may be folded with the calculator therein and easily placed within a pocket.
U.S. Pat. No. 4,096,577, issued to Ferber et al. on June 20, 1978 also discloses a thin electronic calculator housed between two layers of thin flexible vinyl to form one side of a thin, flexible folder, the other side of which carries a pad or business form such as a checkbook.
Calculators also play an increasingly important role in the education process. As part of the curriculum, many school systems now require that students be taught how to use a calculator. In meeting this requirement, it has proved advantageous to instruct students in the use of a calculator by also providing accompanying material, such as a textbook. Instructions as to the use of the calculator can be provided in the textbook. Alternatively, a math book or an accounting book has proven particularly appropriate for instructing in the use of a calculator.
When a calculator is used with an accompanying textbook in the learning process, the two articles actually serve as one learning tool. It is thus advantageous to have the calculator physically attached to the textbook in a manner that does not interfere with normal use of the textbook. At the same time, it would also be convenient if the manner of attaching a calculator to a textbook would provide a non-use position for the attacted calculator and holder, so that the textbook, the calculator and the calculator holder could be stored together during periods of non-use. This would save storage space and/or time in distributing otherwise separate teaching material to students prior to instruction.
Prior inventions have provided means for attaching articles to textbooks. For example, U.S. Pat. No. 3,146,004, issued to Kidd on Aug. 25, 1964 discloses a sleeve for attachment to the cover of a book which is adapted to hold a pad of paper and pencil. After a period of use, the holder is detached from the book and carried in a pocket or handbag. Thus, although Kidd provides an attachment for using a conventional note pad in conjunction with a textbook, the user is still required to carry the holding attachment separately. The convenience provided by having access to a conventional note pad while using a textbook is lost by the fact that the holder, the book and the note pad must be carried separately.
It is therefore desirable to provide a calculator holder for attaching a calculator to a textbook in a manner that does not interfere with the normal use of the textbook for advantageous use in teachning how to use a calculator.
it is also desirable to provide such a calculator holder which remains attached to the book during periods on non-use, so that the textbook, the calculator, and the calculator holder may be conveniently stored together in one place.